Quote Originally Posted by Hsing-ee View Post
Maccari has advice on this, less it more ...

https://www.airrifleheadquarters.com...age/251485.htm
Maccaris advice is good, he has some more on sizing under one of his seal listings:
https://www.airrifleheadquarters.com...485/834669.htm

Quote Originally Posted by Shed tuner View Post
bear in mind a freshly sized seal will wear in very quickly, so do not size to prefection, or it will be too small with a few dozen shots. Size to be too tight, but so you can get it and and move it with a good shove. then shoot 30-40 and it'll probably be fine..
Also good advice. It is very easy to go too far in sizing, looking for the optimal "sliding fit"- and then, after some shooting, the seal ends up undersized.

I prefer a quite high lathe speed when sizing, and using a quite coarse sand paper (180-240 grit). I use it dry, but move it around to avoid clogging.
Try to keep the shape of sealing edges intact.